The combination of a header and a liquid receiver fixed thereto has been placed into use as a condenser in refrigeration cycles providing motor vehicle air conditioners so as to render the condenser easier to install in vehicle bodies and to reduce the installation space. Also placed into use are supercoolers for supercooling the liquid refrigerant as condensed by a condenser to a temperature about 5 to about 15° C. lower than the condensation temperature to achieve improvements in the refrigeration capacity of refrigeration cycles, and heat exchangers of the unit type are introduced into use in which a condenser portion having the function of a condenser and a supercooler portion having the function of a supercooler are provided in the form of a unit.
Such unit-type heat exchangers already known include those comprising a pair of headers extending upward or downward and spaced apart from each other, a plurality of refrigerant tubes arranged one above another in parallel at a spacing between the pair of headers and having opposite ends joined to the respective headers, fins arranged between respective adjacent pairs of refrigerant tubes, and a liquid receiver fixed to one of the headers. The receiver-fixed header and the other header are internally divided at portions thereof positioned at the same level to thereby provide a condenser portion having the function of a condenser and a supercooler portion positioned below the condenser portion and having the function of a supercooler, the receiver-fixed header having fixed to the peripheral wall thereof a receiver connecting block having channels permitting the refrigerant flowing out of the condenser portion to pass through the liquid receiver and to flow into the supercooler portion, the liquid receiver being fixed to the block, the block and the liquid receiver having respective contact faces to be brought into intimate contact with each other. The liquid receiver is fastened to the block with screws, with the contact faces of the block and the receiver in intimate contact with each other (see the publication of JP-A NO. 11-2475).
With the unit-type heat exchanger disclosed in the above publication, however, it is likely that rainwater or the like will ingress into an interstice between the contact faces of the block and the liquid receiver.
Refrigerant passage portions of refrigeration cycles, for example, pipes for use in a piping system of the cycle, are connected to each other by a refrigerant passage portion connecting structure which comprises a block fixed to one of the pipes and having a channel communicating with the pipe, and a block fixed to the other pipe and having a channel communicating with the other pipe, the two blocks having respective fixing portions and respective contact faces each provided on the fixing portion and to be positioned in intimate contact with each other, each of the channels having one end opened in the contact face, the two blocks being fastened together with the contact faces of their fixing portions in intimate contact with each other and with their channels communicating with each other.
However, with such a refrigerant passage portion connecting structure, rainwater or the like is likely to penetrate into an interstice between the contact faces of the two blocks.
An object of the present invention is to overcome the above problems and to provide a heat exchanger which is adapted to prevent rainwater or the like from ingressing into an interstice between the contact faces of a receiver connecting block and a liquid receiver, and a refrigerant passage portion connecting structure which is capable of preventing rainwater or the like from penetrating into an interstice between the contact faces of two blocks.